block: Add blk_get_refcnt()

This function returns the reference count of a given BlockBackend.
For convenience, it returns 0 if the BlockBackend pointer is NULL.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: dfdd8a17dbe3288842840636d2cfe5bb895abcb0.1446475331.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

diff --git a/block/block-backend.c b/block/block-backend.c
index 1ac6982..6f9309f 100644 (file)
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -189,6 +189,11 @@ static void drive_info_del(DriveInfo *dinfo)
     g_free(dinfo);
 }
 
+int blk_get_refcnt(BlockBackend *blk)
+{
+    return blk ? blk->refcnt : 0;
+}
+
 /*
  * Increment @blk's reference count.
  * @blk must not be null.

diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 40e315b..f4a68e2 100644 (file)
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -65,6 +65,7 @@ BlockBackend *blk_new_with_bs(const char *name, Error **errp);
 BlockBackend *blk_new_open(const char *name, const char *filename,
                            const char *reference, QDict *options, int flags,
                            Error **errp);
+int blk_get_refcnt(BlockBackend *blk);
 void blk_ref(BlockBackend *blk);
 void blk_unref(BlockBackend *blk);
 const char *blk_name(BlockBackend *blk);